The basic theory and operation of thermoelectric devices has been developed for many years. Presently available thermoelectric devices used for heating and cooling applications typically include an array of thermoelectric elements which operate in accordance with the Peltier effect.
Thermoelectric devices may be described as essentially small heat pumps which follow the laws of thermodynamics in the same manner as mechanical heat pumps, refrigerators, or any other apparatus used to transfer heat energy. A principal difference is that thermoelectric devices function with solid state electrical components (thermoelectric elements or thermocouples) as compared to more traditional mechanical/fluid heating and cooling components. The efficiency of a thermoelectric device is generally limited to its associated Carnot cycle efficiency reduced by a factor which is dependent upon the thermoelectric figure of merit (ZT) of the materials used in fabrication of the associated thermoelectric elements. Materials used to fabricate other components such as electrical connections, hot plates, and cold plates may also affect the overall efficiency of the resulting thermoelectric device.
Thermoelectric devices may be used in a variety applications. For example, due to the success of car seat cooling units, which rely on thermoelectric devices for temperature regulation, the market for personal cooling technologies has seen a great expansion in recent times.